Cutter grinders



i w. F. FRENCH April 2, 1957 CUTTER 4GRINDERS 4 Sheets-Sheet 1 April 2,1957 w. F. FRENCH 2,787,094

CUTTER GRINDERS Filed. Nov. 22, 1954 4 Sheets-Sheet 2 (U MQ l 1 I L .,l

FIG. 2

WARREN F. FRENCH lNvENToR BY E ATTORNEY April 2, 1957 w. F. FRENCHCUTTER'GRINDERS 4 Sheets-Sheet 3 Filed Nov. 22, 1954 FIG. 6

WARREN F. FRENCH INVENTOR April 2, 1957 w. F. FRENCH CUTTER GRINDERS 4Sheets-Sheet 4 Filed Nov. 22, .1954

Rororionol Axis Y-Yof Diamond Wheel Dreser Dn/O+ Am of wheel Head forClearance Angle Sehinq WARREN F. FRENCH INVENTOR WY i ATTORNEY UnitedStates Patent O CUTTER GRINDERS Warren F. French, Brockton, Mass.,assignor, by mesue assignments, to William H. Field Co., Inc., Boston,Mass., a corporation of Massachusetts Application November 22, 1954,Serial No. 470,267

Claims. (Cl. 51--123) This invention relates to grinding machines, andmore particularly to improvements in cutter grinders. More especially itrelates to an improved cutter grinder for sharpening helical bits,cutters with helical lutes, and like cutting tools, as Well as beingadapted for use in sharpening the cutting edges of various cuttershaving straight ilutes or teeth. The invention contemplates novel andeiective positioning means for setting the height of the work supportingportion of a tooth rest accurately on center with the rotational axes ofboth the grinding Wheel and a cutting tool in a work support. Theinvention further contemplates novel wheel dressing means whereby theannular end grinding surface of a cup-shaped grinding wheel employed togrind a cutting tool will be dressed or reshaped to vary Iaccuratearcuate form or contour laterally of the wheel rim to provide aperipheral datum circle at the point of greatest convexity to which thework contact point of the cutter supporting tooth rest bears asubstantially constant position regardless of the clearance angle beingground on the cutter.

ln the particular form of the embodiment of the invention hereinillustrated, the cutter grinding machine is provided with alongitudinally reciprocable and laterally adjustable work supportingmeans and an angularly adjustable elevatable or altitudinallypositionable grinding wheel head including a cup-shaped grinding wheelhaving an annular end grinding surface provided with a convex peripherylaterally of its rim made by dressing or shaping the same on a radiuscrosswise of the rim so that its convex grinding face is ofsubstantially semi-circular contour. The grinding wheel head includes anangulariy adjustable grinding wheel slide in 'a vertical plane and avertically adjustable carriage on which the wheel slide is mounted. Thegrinding wheel slide is so arranged that its vertical angular adjustmentis about a horizontal line or center lying forward of and parallel withthe horizontal diameter of the operating grinding surface in a planecontaining the rotational axis of the grinding wheel and also passingthrough the tip extremity oi the work supporting contact point of atooth rest which is ilxedly mounted on the wheel head and movable bodilytherewith during any altitudinai and angular adjustment of the wheelhead. The wheel dressing means is mounted for 180 movement in a verticalplane passing through the rotational axis of the grinding Wheel and alsois iixed to the wheel head. The wheel dressing means is arranged 'topivot or swing about a horizontal line or axis parallel with theaforementioned pivot axis of the Wheel head and passing through thecenter of the radius of curvature of convex peripheral end of thegrinding Wheel rim.

Two forms of height setting or gauging means are provided on themachine, one being a hinged arrangement adapted for use in setting oncenter with the axis of the cutter to be sharpened the contact portionof tooth rests of either the fixed type fast on the Wheel head or ablade mounted on a mandrel carrying the cutter to be operated on; andthe other form being a pair of relatively movable plate members, onebeing adapted for use only with helical flute cutting tools and arrangedfor vertical movement with the wheel carriage and the other beingstationary, and each bearing cross markings which are aligned when thewheel carriage is set at the correct height to place the contact pointof the tooth rest on center with the axis of the cutting tool in thework supporting means.

The invention has for one of its objects to provide a cutter grindingmachine wherein the setting of helical ilute or straight uted or toothedcutting tools is simplitied and a predetermined lip clearance can beobtained which is uniform throughout the longitudinal extent of aparticular cutting edge of the tool and can be duplicated upon each ofthe flutes or teeth thereof.

Another object of the invention is to provide a cutter grinding machineof simple andcompact construction Vwhich can be used by a workmanwithout previous experience, and without skilled labor, and by means ofwhich helical or straight luted bits and cutters may be rapidly andaccurately ground and sharpened.

Another object of the invention is to provide a tooth rest for helicalcutting tools xedly supported on a grinding wheel head and adjustableonly laterally thereof in relation to the annular end grinding surfaceof a grinding wheel.

A further object of the invention is to provide a tooth rest for helicalcutting tools in which the contact point of the rest bears asubstantially constant xed relation with a datum circle formed on thegrinding face of the grinding wheel and also is intersected by adiametrical plane containing the wheel axis and the axis of the cuttingtool to be ground.

A still further object of the invention .is the provision of accuratemeans of setting the height of the contact point of a tooth restprecisely on center with the axes of the wheel and the cutter to beground :and without being affected by changes in clearance angles.

Another object of the invention is the provision of radius wheeldressing means to generate a convex grinding surface on the wheel inwhich the point of greatest convexity lies on a peripheral datum circlearound the grinding wheel face and to which the contact point of thetooth rest is xedly positioned.

In the accompanying drawings:

Fig. l is a fragmentary perspective view, partly in section, of a cuttergrinding machine according to the invention, and showing one of theheight setting devices being used to set `the contact point of the toothrest employed in sharpening a helical cutter accurately on center withthe cutter axis;

Fig. 2 is a top plan view of the cutter grinder shown in Fig. l butshowing the articulated height setting device being used in a gaugingposition;

Fig. 3 is an end elevational view, partly in section, of the cuttergrinding machine shown in Figs. 1 and 2 looking at the right end of Fig.2;

Fig. 4 is a fragmentary perspective View, partly in section, of thecutter grinding machine shown in Fig. 2 but showing a milling cuttersupported on a mandrel in grinding position and with the articulatedheight setting device for the tooth rest carried by the mandrel beingswung into a gauging position;

Fig. 5 is a fragmentary pictorial view of the forward end portion of thegrinding wheel` slide showing more or less diagrammatically and in endelevation the cup-shaped grinding wheel partly in section, the toothrest for helical cutters in operating position to the grinding wheel,and the axial disposition of the wheel dressing device to the grindingwheel;

Fig. 6 is a fragmentary top plan view of the cupshaped grinding Wheel`anti tooth rest as shown in Fig.

5 with the grinding wheel partly shown in section so as vto illustratethe rim contour and also the operating poavenues *s sition of the toothrest to the convexed grinding surface; and

Fig. 7 is an enlarged fragmentary side elevational view showing thegrinding operation in progress on a helical bit.

Referring to the drawings in detail, there is shown in Figs. l, 2 and 3a cutter grinding machine embodying the present invention in which thereference numeral 1i) denotes, generally, a grinding wheel head assemblywhich comprises a grinding wheel slide 12 and a supporting carriage 13therefor arranged for vertical movement along suitable dovetailslideways for altitudinal adjustment of the carriage on a bracket 14upstanding from and iixedly mounted on a base member 15 for the machine.Vertical movement of the carriage 13 is by a manually-operatedball-crank machine handle 16 and a suitable feed screw 17. The grindingwheel slide 12 overhangs a laterally extending arm 1S of the carriage 13and is supported for angular adjustment thereon in a vertical planeperpendicular to the plane of vertical altitudinal adjustment of thecarriage by inter-engaging upright arcuatelyshaped lnachine slidemembers 19 and 2t) which are iixed to the outer end of the arm 18 and tothe grinding wheel slide 12, respectively. The grinding wheel slide 12is provided with overhung bearing portions 21 and 22 respectively, whichextend forwardly and rearwardly of the slide and in which is journaled aspindle 23 having removably mounted on its forward end a grinding wheel24 past which is reciprocated a horizontally reciprocable table Z5carrying a work supporting head 26. A V- belt drive is employed fordriving the grinding wheel spindle Z3 from an electric motor 27, thedrive comprising a V-pulley 23 secured on the rear end of the spindle 23and about which passes a V-belt 29 which is driven by a V-pulley 30 onthe shaft of the electric motor 27. The arcuate slides 19 and 2l) areprovided respectively with a graduated scale 31 and a pointer 32 tofacilitate the setting of the grinding wheel slide 12- angularly apredetermined amount for the Wheel to grind the proper clearance angleon the cutter.

The grinding wheel 24 is of cylindrical cup-shaped form and, in theillustrated arrangement of the machine as shown in Figs. l, 2 and 3 ofthe drawings, is formed with an annular convexedly curved end grindingsurface 33 which is operatively arranged in proper relation to the workcontact point 34 of a tooth rest 3S to grind the peripheral edge of theparticular iluted portion of a helical bit or cutter herein designatedby the letter W (see Fig. 7), as will be hereinafter described.

The tooth rest 35 for helically iluted cutting tools is attached to thewheel head 12 in an oifset position alongside of the grinding wheel 24and is adjustably mounted and clamped 'in a suitable channeled guideway36 (see Fig. 4) formed in the side of an enlarged end portion 37 of thefront bearing portion 21 for longitudinal adjustment only in theguideway 36 for setting of the contact point 34 of the tooth restcorrectly to the end grinding surface 33 of the grinding wheel. It willbe noted that the grinding wheel slide 12 is mounted for verticalangular adjustment on a horizontal line X--X lying in a plane at rightangles to the rotational axis of the grinding wheel spindle 23 (seeFigs. l and 5). For the purpose of so adjusting the grinding wheel slide12, there is journaled in this slide a hand screw 38 having suitablepivotal connection (not shown) at its bottom end with the arm portion 18of the carriage 13 whereby upon appropriate manual turning of the screw38 the arcuate slide member Ztl will be moved in the arcuate guideway ofthe slide member 19 and together with the wheel slide 12 will beangularly adjusted in any desired position in a radial line which isnormal to the axis X-X about which the grinding wheel slide 12 isadjustable. The slide 12 is secured in place in its adjusted Ioroperating positionl 4 ber 20 and slidably passing through an arcuateslot 41 (see Fig. 3) in the arcuate slide member 19.

The table 25 is .slidably mounted for longitudinal reciprocation upon atransversely adjustable slide 44 by means of free-moving, anti-frictionrollers 45 engaging a V-edged plate or track member 46 which extendslongitudinally beneath the table 25 and is mounted in a crosswiserelation upon the slide dll, as shown in Figs. 3 and 4. The table 25 ishand-propelled by the machine operator past the annular end grinding,surface 33 of the grinding wheel 24 in a direction at right angles tothe axis of the grinding wheel spindle 23 during grinding of a bit orother cutting tool and returned to its initial position at the right endof the machine by means of a suitable spring (not shown) operativelyconnected with the table 25 and the slide 44 and adjustably tensioned bya hand screw device 47. The transverse slide 44, in turn, is operativelyarranged for longitudinal sliding movement back and forth on suitabledove-tail ways of a guide member 43 by means of a suitable feed screwindicated at 49 turned in a threaded portion 49 of the guide member 4Sby an operating handle 5G. The work head 26 here shown is of a knownconstruction and provided with an inflexible work-supporting collet 51which may be rendered freely rotatable by release of a pin plunger 52,and this collet is arranged in a known manner for longitudinal movementin a large hub member 53 overhanging a disc-like base member 54 or' thework head. T he hub member 53 is pivoted in the upper part of an uprightarm 55 integral with the base member 54 of the work head and is adaptedfor angular adiustment on this arm in a vertical plane by means of anoperating lever 56 as well as being adjustable angularly in a horizontalplane by rotary movement of the work head base member S4 about avertical axis here shown as the central mounting stud 57 which securesthe work head 26 to the top of the table 25. An enlarged hand-operatedclamping nut 58 having operative connection with the usual threadedshank end of the collet 51 operates to draw it longitudinally withrespect to the hub member 53 to effect tight clamping of either a bitshank or a cutter .supporting arbor in the collet Sl.

To properly shape `the annular and convexedly curved end face 33 of thegrinding wheel 2li so that it will be of the proper arcuate form withits crown opposite the contact point 34 of the .tooth rest 35 and lyingon a peripheral datum circle D around the end face of 4the wheel, it isnecessary that the dressing or reshaping operation be carried out on anarcuate line lying in a vertical plane which includes the rotationalaxis of tie grinding wheel 24 and which is generated about horizontalaxis Y-Y about which the wheel dressing device revolves in forming theconvexed end grinding surface 33 of the grinding wheel. .ln the presentillustrative disclosure, the radius wheel truing or dressing meansassociated with the grinding wheel 24 and indicated at di) is amicrometer device comprising a diamond 61 mounted in the end of aspindle and lead screw 62 threaded in a barrel 63 which Iis fixed in ahub portion del of a vertical swinging arm 65. The arm 65 has 180pivotal movement by pin 66 on a bracket 67 attached to a dovetail slide655 which caps the top of the enlargement 3? of the grinding wheel slide12 and is arranged to be adjusted and clamped by a suitable .stud in anyadjusted position thereon. A beveled thirnble di? is rigidly fixed tothe lead screw and spindle 62 and fits down over the barrel 63 but doesnot engage it. The beveled end of the thimble 69 is suitably graduatedaround its circumference, and one side of the barrel lalso is markedwith suitable graduations in 1a longitudinal line `for accurateadjustment of the position of the diamond point. rthe swinging arm 55has a handle 79 for moving the point of the diamond 61 back and forthcrosswise of the rim of the annular end face 33 of the grinding wheel 2das indicated in Fig. 5 in order to true and/ or dress the grindingsurface thereof and give it the desired semi-circular arcuate contour.

Means are provided for setting the height of a tooth rest on center withthe axis of the work to be ground and for positioning a particularcutting edge to be ground in a horizontal plane passing through the axisof the cutting tool held by the work support 26. In .the illustratedembodiment, two distinct and separate height setting devices designatedgenerally by ythe numerals 70 and 71 are provided on the machine as.shown in Figs. l to 4 inclusive of the drawings to facilitate thispositioning of the tooth rest and the lip of the cutter. The heightsetting device 70 is made up of -two plates 72 and 73 of which theformer is attached to the side of the carriage 113 `and the latter fixedon the side of the bracket 14, both being mounted close to the verticalpartingy line between the carriage and the bracket. Each plate is markedcross-wise with ya centering line as indicated at 74 which lines arebrought into horizontal alignment one with the other as depicted in Fig.1 and indicate that the -altitudinal adjustment of the grinding head iscorrectly positioned to place the contact point 34 of the tooth rest 35and lthe cutting edge of the cutter lip correctly on center with theaxis of the cutter being sharpened. The second height setting device 71herein illustrated is an articulated gauge arrangement which ispivotally mounted on the top surface of a at plate-like projection 75extending laterally outwardly from the side of the work support 26, asshown in Figs. l, 2, 3 and 4. The gauging device 71 comprises threepivotally connected horizontally disposed arm members 76, 77 and 78 ofwhich the arm 76 is pivotally mounted at its inner end on the topsurface of the projection 75, fthe arm 77 has swinging movement underthe outer end portion of the arm 76, and the arm 78 constitutes thefeeler finger of the gauge and is positioned on top of the arm 77 at itsouter end. The horizontally disposed gauging surfaces of the device,viz., the top surface of the projectio-n 75, the bottom surface of thearm 76, the top surface of the arm 77, and the bottom `'surface of thefeeler `arm 78 all are precision-ground or lapped absolutely flatsurfaces throughout their entire extent. It should be noted that theflat top surface of the projection 75 exactly lies in a horizontal planepassing .through the longitudinal axis of the work-supporting collet 51and, consequently, the rotational axis of the cutter to be Vground whenheld in the work support 26. The arms 76, 77 and 78 of the gaugingdevice 71 are adjustable with respect to each other and the entiredevice 71 may be swung aside into an inactive position when not in use,as depicted in broken outline in Figs. l and 2. Y

In sharpening helical bits or helical flute cutters with the apparatusabove-described, the grinding wheel slide 12 may be set rst to theproper clearance angle, such as for example, ten degrees from verticalaccording to the scale 31 and pointer 32. Then, the grinding wheel 24 isdressed by means `of the radius wheel dressing device 6d to provide laconvex grinding surface 33 on the annu' lar end face of the grindingwheel. Prior to this dressing operation or at the completion thereof theproper size and hand of tooth rest 35 is mounted in position in thechannel-shaped groove 36 of the portion 37 of the grinding wheel slide12 yand the work contact point 34 of the tooth rest adjusted to place itclose to the convex end grinding face 33 of .the wheel but withouttouching the wheel surface, i. e., approximately .010 of an inch, andalso in juxtaposition with the4 datum circle D of the wheel. Then theheight gauge 7l is swung around as indicated in Figs. l and 2 so thatthe flat bottom gauging surface of the feeler ar-m 78 of the heightgauge 71 extends over and touches the tip of the contact point 34 of thetooth rest, the elevation of the grinding wheel 24 and the wheel head 10being adjusted by appropriately raising or lowering movements of thecarriage 1-3 on the bracket 14 by means 'of the ball-crank handle 16 andfeed screw 17. When thus set, the height gauge is swung aside out of theway as depicted in Figs. l and 2. If, however, it is desired to use theheight setting means in lieu of the |articulated arm device 71, then thecontact point 34 of the tooth rest 35 is set on center in `a horizontalplane with the axis of the cutting tool by adjusting the altitudinalposition of the wheel head 10 by the ball-crank handle 16 and feed screw17 until both cross centering lines 74 on the side plates 72 and 73 arelongitudinally aligned thereby indicating that the tip of the contactpoint 34 of the tooth rest 35 is set on center in a horizontal planepassing through the axis of the cutter or bit. Regardless of whichgauging or setting means is employed, the tip of the contact point 34 ofthe tooth rest 35 will lie in a plane containing the grinding wheel axisand the line X-X about which the grinding wheel slide 12 is angularlyadjusted.

During the grinding operation on cutting tools, such as helical bits andcutters having helical tintes, it is merely necessary to insert theshank of the cutting tool to be sharpened in the work-supporting collet5l, after which the traverse slide 44 together with the table 25 and thework head 26 is fed inwardly by appropriate movement of the operatinghandle 50 until the lip of a particular flute of the cutting toolengages over and is supported by the contact point 34 of .the tooth rest35. The cutting tool then is moved longitudinal-ly past the grindingWheel 24 while in engagement with its rounded end grinding :face bymanual reciprocation of the sliding table 25 While holding the toolrevolved and pressed against the contact point 34 of the tooth rest bymeans of the collet clamping nut 5S. in this way, as the cutting tool ismoved lengthwise the helical lead `of its cutting edge or lip will turnthe cutting tool about its own axis in the work support 26, since it isnow freely turnable therein due to previous releasing movement of thepin plunger 52, and thereby will bring successive portions of thehelical flute being operated by the grinding wheel into the propergrinding plane while thus supported by the tooth rest anduntil thecutting tool stops turning when the end of the particular helical ute isreached. This procedure may be repeated several times for each ute landuntil all the lips of all of the cutting tool have been ground andsharpened. The helical bits or cutting tools to be ground can be anylength, four inches being usually the maximum limit for router bits. Thesize, angle and hand of helix of the contact point 34 of the tooth rest35 will, of course, depend upon the hand and angularity of the twist orlead of the helical cutting edge of the particular cutting tool to beground and, in practice,

many possible combinations of helix and hand of cut are possible so thata number of appropriate hands of tooth rests are used to meet thevarious requirements of helical ute bits and cutters operated upon bythe grinding machine.

In the event that a straight fluted cutting tool, such as a millingcutter C is to be sharpened, reference is made to Fig. 4 of the drawingsin which a milling cutter C having the cutting edges of its straightteeth to be ground by the cup wheel 24 is mounted for free rotation upona suitable shaft portion (not shown) of a mandrel herein designatedgenerally by the reference numeral which is supported in thehorizontally extending overhanging fashion hereshown by a shank portion(not shown) held fixed in the collet 51 of the work support 26. A spring83 acting between the rear side of the cutter C and a clamping nut 84exerts a restraining force against the cutter C to prevent it fromturning too freely on the mandrel during indexing of the cutter teeth aswell as serving to keep the cutter C square with the cylindrical face ofits supporting shaft portion of the mandrel 80. A flexible tooth rest 85consisting of a blade member made of at sheet spring stock is adjustablymounted in a laterally extending position on the outer end of a barmember 86, which in Aturn is slidably mounted in and adjustable radiallyof a hub portion 87 of the mandrel S0. The tooth rest blade 85 islongitudinally slotted as indicated at 88 to permit its height to be setrelative to a particular tooth of the cutter C on the mandrel afterwhich the tooth rest is clamped in place in its set position by means ofa stud 90 and washer 91. The specific construction of this cuttergrinding mandrel 80 with tooth rest 85 forms no part of the presentinvention since its structure forms the subject matter disclosed andclaimed in my copending application, Serial No. 445,003 which was filedJuly 22, 1954 and has since led to Patent No. 2,725,690, grantedDecember 6, 1955.

From the above description it will be apparent that I have provided anovel cutter grinder adapted to grind helical flute bits and likecutting tools as well as milling cutters having straight peripheralteeth in a simple and accurate manner, the grinder being of compact formadapted to be mounted upon a bench and to be operated by a comparativelyunskilled workman or one without previous experience in cutter grinding.It will also be apparent that by reason of the novel mountingarrangement of the grinding wheel head the whole grinding wheel slide 12including the grinding wheel 24 itself is angularly adjustable to grinddesired clearance angles on the cutting tool and the angular movement ofthe grinding wheel slide is about a line or axis passing substantiallythrough the contact point of a tooth rest which remains in fixed heightrelation and on center with the work axis when once set in this positionby use of either of the height setting devices 7i) or 71 whichconstitute one feature of my invention. Thus by my improved mountingarrangement of the wheel head I have obviated the prior generalprocedure of separately making adjustments to bring the center of thewheel and the work as Well as the contact portion of the tooth rest allinto the same plane and then raising or lowering the wheel head (or thetable) the proper distance to give the desired clearance angle sincewith my machine the tooth rest contact point position is fixed by itsmounting on the wheel slide 12 and maintained in a predeterminedrelation to the grinding surface 33 of the grinding wheel 34 where itremains unaffected by clearance angle adjustments by reason of theangular positioning of the grinding wheel slide 12.

While l have described a preferred form of my invention, it is to beunderstood that various modifications and changes in form and details ofconstruction may be made therein within the range of engineering skillwithout departing from the spirit and scope of the invention as definedin the appended claims, and it is therefore my intention not to limit myinvention in any manner Whatsoever except by the terms and scope of theappended claims.

What is claimed is:

l. In a machine for grinding helical cutting tools the combination of agrinding wheel head adjustable for altitudinal movement in a verticalplane and also angularly in a lateral direction in a vertical planeperpendicular to said vertical plane of altitudinal adjustment of thewheel head, a grinding wheel spindle rotatable on said wheel head, agrinding wheel carried by said spindle, a work support for supporting acutting tool to be sharpened and provided with a gauging surface iixedlypositioned in a horizontal plane containing the axis of said worksupport, said work support being movable longitudinally past thegrinding surface of said Wheel and also adjustable laterally toward andfrom said grinding surface, a tooth rest mounted on said wheel head andhaving a tooth contact point set close to but clearY of the grindingsurface of said wheel, the tooth contacting tip of said tooth rest pointcoinciding with a horizontal line normal to the wheel axis and lying ina diametrical plane containing the axes of said spindle and the grindingwheel, and also including the axis of said work support, and

height setting means for the tooth rest movably arranged on said gaugingsurface and including aY-feeler element to be brought from an inactiveposition into a position coincident with said diametrical plane toestablish an accurate placement of the tip of the contact point of saidtooth rest exactly on center with the axis of a cutting tool in saidwork support as the vertical altitudinal adjustment of the wheel head ismade in the appropriate direction, said tooth rest having bodilymovement with said wheel head during adjusting movements thereof bothaltitudinally and angularly in their respective vertical planes duringwhich the tip of the work contact point of the tooth rest maintains aconstant position in relation to the grinding surface of the wheelunaffected by predetermined changes in clearance angles.

2. In a machine for grinding helical cutting tools the combination of agrinding wheel head adjustable for altitudinal movement in a verticalplane and also angularly in a lateral direction in a vertical planeperpendicular to said vertical plane of altitudinal adjustment of thewheel head, a grinding wheel journaled in said wheel head, a cupshapedgrinding wheel carried by said spindle, a rotatable work support forholding a cutting tool to be sharpened and provided with a flat gaugingsurface tixedly positioned in a horizontal plane containing the axis ofsaid work support, said Work support being movable longitudinally pastthe end grinding surface of said cup wheel and also adjustable laterallytoward and from said grinding surface, a tooth rest mounted on saidwheel head and having a tooth contact point set close to but clear ofsaid grinding surface of the Wheel, the toothcontacting tip of saidtooth rest point coinciding with a horizontal line normal to the wheelaxis and lying in a diametrical plane containing the axes of saidspindle and the grinding wheel, and also including the axis of saidwheel support, and height setting means for the tooth rest movablyarranged on said gauging surface and including a feeler element to bebrought from an inactive position into a position coincident with saiddiametrical plane to establish an accurate placement of the tip of thecontact point of said tooth rest exactly on center With the axis of acutting tool in said work support as the vertical altitudinal adjustmentof the wheel head is made in the appropriate direction.

3. The combination claimed in claim 2 in which the height setting means`consists of a series of articulated elongated Iarm members, one of theend arms being pivotally mounted on the cutter holding work support andsupported lby said tiat gauging surface thereof placed exactly on centerwith the work support axis and the distal end arm lhaving la flatundersurface accurately aligned with the first-named surface to serve asa gauging surface for the setting of the tooth-contacting tip portion ofsaid tooth rest on exactly center with the `axis of Ia cutter to beground.

4. The combination claimed in `claim 2 in which the cup wheel has aconvex grinding surface transversely of its rim `and with the crown ofsaid surface opposite the tooth contact point of the tooth rest andlying on a peripheral datum circle around the Vend face of the wheel,and a radius wheel dressing device is provided in which the Idressingtool moves in an arcuate path lying in a vertical plane which includestherrotational axis of the grinding wheel and which is generated about ahorizontal axis about which the wheel `dressing device is Iarranged torevolve so as to form said convex grinding surface on the wheel withsaid crown portion thereof correlated to said tooth contact point of therest.

5. in a cutter grinding machine, the combination of a grinding wheelhaving an annular grinding face, elevatable `support means for saidgrinding wheel including a spindle on one end of which said grindingwheel is secured, means for rotating said grinding wheel spindle, a worksupport reciprocable past said annular grinding face of said wheel andadjustable laterally toward and away from such wheel face, and heightgauge means pivotally mounted on a lateralextending portion of said worksupport and which forms a perfectly flat gauging surface thereon iixedlypositioned in a horizontal plane containing the axis of said worksupport, said gauge means further having a feeler member the undersideof which is perfectly liat and disposed in a horizontal plane thatexactly coincides with s-aid horizontal plane containing the rotationalaxis of the cutter to be sharpened, said height gauge means also beingarticulated and arranged to be swung from an inoperative position vintoIan operating position to place the feeler portion of such gaugeopposite the end grinding face of said wheel to engage the tooth contactpoint of a tooth rest and there-by position it accurately on center withthe rotational axis of a cutter when the grinding wheel support means ismanually adjusted vertically to effect such engagement of the contactpoint of such tooth rest with the nnderface of the feeler member.

6. In a grinding machine, the combination of "a cupshaped grindingwheel, vertically elevatable and vertically angularly adjustable supportmeans for said grinding wheel including a spindle on one end of whichsaid grinding wheel is removably secured, means for rotating saidgrinding wheel spindle, 'a tooth rest mounted on said grinding whe-elsupport means and having a tooth contacting portion placed inpredetermined fixed relation to the annular end grinding face of theannular end grinding wheel, a work support reciprocable past thegrinding face of said wheel and adjustable laterally toward and awayfrom such wheel face, and height gauge means pivotally mounted on alateral extending portion of said work support and which forms aperfectly flat gauging surface thereon iixedly positioned in ahorizontal plane containing the axis of said work support, said gaugemeans further having a feeler member the underside of which is perfectlyilat and disposed in a horizontal plane that exactly coincides with saidhorizontal plane containing lthe rotational axis of the cutter to besharpened, said height gauge means also rbeing articulated and arrangedto be swung from an inoperative position into an operating position toplace the feeler portion of such gauge opposite the end grinding face`of said wheel to engage the tooth contact point of the tooth rest yandthereby position it accurately on center with the rotational axis of acutter when the grinding wheel support means is manually adjusted toeffect such engagement of the contact point of the tooth rest with theunderface of said feeler member.

7. In a grinding machine, the combination as set forth in claim in whichthe end cutting face of the grinding wheel is convexedly curved in asemi-circular arc to form a convex grinding surface Whose crown facesopposite the tooth contact point of 'the rest and lies on a peripheraldatum circle around said end wheel face and a radial wheel dressingdevice is provided in which the dressing tool moves in an arcuate pathlying in a vertical plane which includes the rotational axis of thegrinding wheel vand which is generated about a horizontal axis aboutywhich the wheel dressing device is arranged 'to revolve so as to formsaid convex grinding surface on the wheel with said crown portionthereof correlated to said tooth contact point of the rest.

8. ln a cutter grinding machine of the character described, a basehaving lan upstanding support member; a carriage mounted upon saidsupport member for vertical sliding movement into desired altitudinallyadjusted positions, said carriage having a laterally extending arm; anarcuate member affixed to said carri-age arm and disposed laterallythereof in Ia vertical plane, said arcuate member having a longitudinalarcuate guideway; a movable wheel slide including an arcuate supportmember engaging in and guided `by said arcuate guideway when movedlongitudinally therein to adjust said Wheel slide angularly in avertical plane or to position it horizontally; a cup-shaped grindingwheel rotatable on said wheel `1`0 slide rand disposed in overhungrelationship thereto; a tooth rest mounted in an offset position on saidwheel slide and adjustable thereon for placement of a cutter rtoothcontact portion of said rest ina predetermined fixed position to theannular end grinding `surface of said wheel;

a table mounted on said base 'below said grinding wheel and arranged formovement longitudinally pastsaid end grinding surface of the wheel andalso adjustable laterally toward `and from such wheel surface, saidtableincluding work support means provided with a laterally extending portionhaving a perfectly fiat horizont-al gauging surface xedly positioned ina horizontal plane passing through the longitudinal axis of said worksupport means; and height gauge means composed of a plurality ofpivotally articulated members including an end feeler element having aperfectly flat undersurface portion, said height gauge means beingpivotally mounted by the Iarticulated mem- Iber distal from said feelerelement against the iiat -horizontal gauging surface portion of thelaterally extending portion of said work support means, said heightgauge means being arranged to be swung from an inoperative position intoan operating position to place the feeler element of vsuch gaugeopposite the end grinding surface of said wheel and above the contactpoint of `said tooth rest for engaging such contact point and positionit exactly on center with the axis of said support means when thegrinding wheel slide is manually adjusted in elevation to ybring aboutengagement of the contact point of said tooth rest with the undersurfaceof said feeler element of the height gauge.

9. The combination as claimed in claim 8 in which the cup-'shapedgrinding wheel has an annular end grinding surface which is convexedlycurved in a radial direction of the grinding wheel and presents a convexgrinding surface whose crown faces opposite the tooth contact point ofthe rest and lies on a peripheral datum circle around said end wheelface, and a radius wheel dressing device is provided in which thedressing tool moves in an arcuate path lying in a vertical plane whichincludes the rotational axis of the grinding wheel 4and which isgenerated about a horizont-al axis about which the wheel dressing deviceis arranged to revolve so as to form said convex grinding surface on thewheel with said crown portion thereof correlated to said tooth contactpoint of the rest.

l0. in a cutter grinding machine of the character described, a basehaving an upstanding support member; ya carriage mounted upon saidsupport member for vertical -sliding movement into desired altitudinallyadjusted positions, said carriage having a laterally extending arm; anlarcuate member aixed to said :carriage arm and disposed laterallythereof in a vertical plane, said arcuate member having a longitudinalguideway; a movable wheel slide including an arcuate support memberengaging in and guided by said arcuate guideway when movedlongitudinally therein to adjust said w-heel slide angularly in avertical plane, or to position it horizontally; a cupshaped grindingwheel rotatable on said wheel slide and having an annular end grindingsurface convexedly curved in a radial direction; means operativelyarranged for adjusting and securing said wheel slide in a desiredadjusted position to support said grinding wheel in ya predeterminedoperating position; a table including work support means mounted on said'base below said grinding wheel and arranged for movement longitudinallypast said end grinding surface of the wheel and also adjustablelaterally toward and from said wheel surface, said work support meanshaving a flat gauging surface flxedly positioned in a horizontal planecontaining the axis of said work `support means; and height settingmeans for a tooth rest movably arranged on said gauging surface andincluding a feeler element arranged to be brought 4from an inactiveposition into a position aligned with said gauging surface to engage andt-o establish an accurate 'T1 placement. of the' tooth contact portionof such tooth restexactiy on center with lthe vaxis uf a cuttersupported by said work `support means and as the vertical altitudinaladjustment of said carriage is `made in the appropriate direction.

References Cited in the file of this patent UNITED STATES PATENTS727,981 Lomasney May 12, 1903 IZ Y Perkins Aug. 1, 1916 Curtis July 11,1933 Anderson July 18, 1933 Wildhaber Aug. 7, 1945 FOREIGN PATENTS GreatBritain Oct. 29, 1931 Great Britain Feb. 17, 1954

